Speed governor having its output and speeder spring automatically modified



Aprll 13, 1954 G. B. R. FEILDEN 2,675,220

' SPEED GOVERNOR HAVING ITS OUTPUT AND SPEEDER SPRING AUTOMATICALLYMODIFIED Filed April 10, 1955 2 Sheets-Sheetl In men for 4190 rue VffApril 13, 1954 G. B. R. FEILDEN SPEED GOVERNOR HAVING ITS OUTPUT ANDSPEEDER SPRING AUTOMATICALLY MODIFIED Filed April 10, 1953 2Sheets-Sheet 2 Patented Apr. 13, 1954 SPEED GOVERNOR HAVING ITS OUTPUTAND SPEEDER SPRING AUTOMATICALLY MODIFIED Geoffrey B. R.

to Ruston & Horns land, a British company Application April 10, 1953,Serial N 0. 348,012

Claims priority, application Great Britain April 15, 1952 12 Claims.

This invention relates to an engine speed governor of the typecomprising a, flyweight system loaded by a speeder spring andcontrolling a pilot valve, and a hydraulic motor actuating the powerregulator of the governed engine and controlled by the pilot valve, withor without means conferring a permanent drooping characteristic, andincluding means conferring a temporary drooping characteristic, suchmeans comprising a mechanical linkage so interconnecting the pilotvalve, the movable member of the hydraulic motor and a resilient devicethat the latter acts as an auxiliary speeder spring, and thatdisplacement or th movable member of the motor in the sense to reducethe power output of the engine causes th extension of the resilientdevice to vary in the sense to augment the total speeder spring-elicit,and conversely, together with a dashpot device operative to allow thespeeder spring-augmenting or -diminishing eifort of the resilientdevice, due to a displacement of the movable member of the motor, todecay at a predetermined rate to zero or to a value substantially lessthan its initial value.

An object of this invention is an improved and simplified governor ofthis type, achieved by combining the said resilient and dashpot devicesin a single component.

A further object of the invention is a governor of the kind specified inwhich the need for an additional auxiliary speeder spring is eliminatedby using a pneumatic device, in which the rate of decay of the speederspring-augmenting or -diminishing efiort, furnished by superatmosphericor subatrnospheric pressure in the pneumatic device, is controllable bymeans of an adjustable atmospheric leak.

According to this invention, the combined resilient and dashpot deviceis constituted by a pneumatic dashpot, or buffer, having a fixedanchorage on the body of the governor and a movable member connected tothe hereinbefore mentioned mechanical linkage, the chamber of thedashpot being provided with an atmospheric leak furnished with anadjustable restrictor.

A pneumatic dashpot possesses the advantags that its operation issubstantially unaffected by changes of temperature, which cause largechanges of viscosity of oil or hydraulic fluids and consequently affectthe rate of synchronisation of governors in which the temporary droopdepends on the action of an hydraulic dashpot or on the communication ofmotion or pressure, from the movable member of the motor to the pilotvalve or to an auxiliary valve memberor Feilden, Lincoln, England,assignor by Limited, Lincoln, Engto the abutment of a spring acting onthe pilot valve, by means of a column of oil or hydraulic fluid. The useof a pneumatic buiier also eliminates the need for an additional spring.

In carrying out this invention, the pneumatic droop due to the pneumaticeffort of the buffer;

The effort exerted by the elasticity of the bellows will, however, bebeneficial in suppressing backlash in the mechanical linkage.

Additional means for conferring a permanent droop of adjustablemagnitude are preferably provided, for example a mechanical linkage of aknown kind connecting the movable member of the motor with the speederspring abutment and having adjustable means for varying its mechanicaltransmission ratio. By providing a range of adjustment enabling thepermanent droop conferred by this linkage to be varied between apositive and a negative limit, the positive droop conferred by theelasticity of the bellows can be augmented or decreased, or, if desired,exactly compensated so governor isochronous.

Another object of the invention is the provision of a simple method andmeans for adjusting the magnitude of the temporary droopingcharacteristic conferred by the pneumatic bufier, the method consistingin partially filling the buffer chamber with oil, preferably thin oil,and adjusting the quantity of oil contained in the chamber to adjust theclearance volume of the chamber, and hence the effective spring rate ofthe pneumatic buffer, and the means consisting in providing the bufferchamber the oil, closable by a plug.

A specific embodiment of the invention is illustrated by way of examplein the accompanying drawings, and is hereinafter described withreference thereto, Without implied limitation of the scope of theinvention as defined in the annexed claims. In the drawings,

Figure 1 is a sectional elevation of the overnor in a plane containingthe axes of the hydraulic motor and of the pilot valve and flyweightsystem;

Figure 2 is a transverse section on the line 2-42 of Figure 1; and

of the speeder spring and varyas to render the with a filling hole forFigures 3 and 4 are fragmentary sections on the lines 3- 3 and 4 --4,respectively, of Figure 1. Referririg to {the drawings, the governorcomprises a body I'Il nfade in several pieces for convenience ofassembly and dismantling. The left hand end of the body, as viewed inFigure 1, carries a bearing I I in which is supported a shaft I2 drivenby the governed "GI'iIgiILQjbIlTOilgh *an appropriate transmissionsystem (not illustrated) Shaft I2 is formed integrally on a flyweightcarrier I3 to which is secured an extension IA axially bored to providea spigot bearing on an internal boss l5 of the body. This bearing islubricated by oil fed through a branch gallery l fifrom the main inletgallery I'I of the governor connected to a source of oil under pressure.Cranks I8 carrying flyweights are pivotally mountedat I9 on the carrierl3, and the toes of cranks I-B carry antifriction rollersZ-ll mounted onball bearings. l'tpllers 2Il bear onthe enlarged head 2! of a pilotvalve "22 slid' s and rotates in a cylindrical bore of ody. Thepil'otvalve is w of the rly'w'eight, by a mares, ag t me e rt wear rs ,s..ifl. l q s ai n car It a thrustbearing 25, a cap member 26 and a thrustbea 21 i i lot Valveis fpressure balan bein waisted on ca fsijde offasingle land 28 to provide two arm 7 oilyvays'of which the right-hand one(as seen lj igiire l) communicatesiwith'the re sii si'j l mi t flfsiilft rh n ested ib rs sl wfl u s rte n. th left-hand end of the pilot v 12. m the constant-speedingfiduilibriii in QQSltIQIl as 'shown in Figurel, lafid 2B esters without 1 2 a pert 29 communieatingwith"a'liydfaulicinothr' cylinder 36 formed inthebod'y. A'pi t as des-1hcylinder 3t, and whenthe pilot 1s idis'pl'aoedjfrornthe eonstaffediri'gpositi'ontothe leftas viewed in Figs 1 ,-"pre ur'e oil'i's"admitted to the lefthand'f'aiceof tan -3I tofrnove it to the right.Piston 3] (i peratesaro d tflwhich slides in a bushing and'i'shelillin'cofitaot with the piston by a i3 itr apped betw'ena shoulder onthe bushi gcarid acollar SS 's'eciiredto the iro dltg. Spring factsth'erturnspring'f'or piston '3 I whi'ch'with r -32c sewerageimevabiemeberfof the hydraulic'motbr 'D'i'spl'a ernehtiof the pilot valve'toftherig'htfrm disposition of Figure rider '30 "and A allows spring" 34 to toreceive the bulbous head of'ail'evr '3'Eniounted on-an abutment"locating member 4 I, which can also slide in'the bore"39. Memberfll isconnected by coaxial pivots "42 ('seea-lso Figure 4:) with 'a lever 43whose-lower extremity '44 is formed as "a striking forken gaginga neckedextension of the rod 32. This engagement prevents"thelever-43fromrotating about-the axis of the bore 35, and since 3 relative 5movement between lever 23 and member "4 I can only take'plac'e abouttheaxis of pivot 42 which'is serpent-reunite the a-xis of'bore 39, themember 4| is prevented frm 'rotating-insurface of the speeder springetflare cut worm-wheel teeth 49 engaged'bya wormfiil mounted on a shaft5! journalled in the body and provided with external means (notillustrated) for rotating it to cause the Speeder spring abutmentthimble 38 to advanceorretirealong the lead-screw 4B and thereby varyits axial spacing from the abutment locating member 4|.

The cap member 25, axially located on the pilot valve 22 by the bearing21, is connected by coaxial pivot pins 52 with a lever 53 in the form ofa plate having a clearance aperture 5 5 accommodating'th'e cap '26 andanother clearance aperture 55 accommoda'ting'rod 32 and spring 34 (seealso Figure 2). At its lower end lever 53 has a knife edge 56 held incontact with piston 3| by asp'ring 5'1 abutting against a collar 5'8secured toastud 5'9 screwed intothe piston. A clearance notchfifi inlever 53 accommodates stud 59.

The upper end of lever 53 is connected by a rod SI having a certainamount of flexibility with a disc 62 to'whos'e circumferenceis attachedone end'of a metallic flexible bellows 63, the other end of which isattached to the margin of an opening in a plate'tfl secured over theopen end of a'cylindrical bore '65 in the body. The plate fi L'bellows53 and disc 62 form a gas-tight closure of "the'cylinder B5, enclosing'achamber 66 of variable volume, which'is vented to atmosphere through apassage 61, an adjustable restrictor 68,159,10 and an atmospheric vent"II. The restrictor isconstituted by a screw plug 68 whichhasa stem '69of reduced diameter fitting closely into passage 61 and provided withtapered flutes T5. The latter provide a leak from the passag'e '61to'a'clearan'ce round the" stem 69 communicating with the vent "'II, thecross-sectional area of the leakage path being adjustable "byscrewing'the plug'fia in and out.

Inthis governor the flyweight system I3, I8, I'9, 2G,loaded by theSpeeder spring23 controls the pilot valve 22, which in tui'n controlsthehydraulic motor '30, "3I, 32, 34,35,31 actuating the power regulator ofthe governed engine. Under-speeding causes "the pilot valve to 'inoveto'theleft' and admit 'oil to cylinder 33 and move piston 3I and rod 32to the right, thusmov'ing levers '35, 31 'to increase engine poweroutput. Conversely, over-speeding causes the pilot valve to'move 'to"the right'an'd vent the cylinder "30, causing lever '31 to decrease theengine'power output. e

A temporary drooping characteristic is coni erred on the governor] bythe mechanical linkage, constituted by the lever 53 "and rod 6 Iconmeeting the pilotvalve 22 through the cap' member 26 and bearing-21)the movable member' 'iii 32 of the hydraulic rnotor and the coinb'ir-iedresilient and -dashpot device, in'the form bfa pneumatic b'uifer,-'constituted by the variable vided by -the elast'icity of the anentrappedsn the chamber 66-, the dashpot action, operative to allowdelayed restoration of the resilient pneumatic effort of the buffer toits former value after a displacement of piston 3|, being provided bythe atmospheric leak 61, 10, H, and the rate of synchronisation aftersuch a displacement being regulatable by adjusting the restrictor 68,69, 10.

Under constant speeding conditions, the pilot valve land 28, having nolap on the fixed port 29, is always in exact register with this port,and consequently under these conditions the position of the pivot axis52 is always the same. The lever 53 may therefore be regarded as havinga fixed fulcrum 52 in constant speeding conditions and the position ofdisc 62 and hence the volume of chamber 66, varies linearly with theposition of piston 3|, being increased by displacement of piston 3! tothe right (as viewed in Figure 1), corresponding to increase of load onthe engine, and conversely. If the leak Bl-ll were closed, the pressurein chamber 66 would vary inversely as the volume under isothermalconditionswhich will obtain approximately in practice except for veryrapid changes of volume-and consequently the effort exerted on the lever53, and. hence on the pilot valve 22, by the pneumatic buifer, due tothe elasticity of its contained air, would vary linearly with theposition of piston 3|, in such a way that the algebraic sum of thiseffort and that of the speeder spring would decrease as the piston isdisplaced to the right, and conversely. This is the condition forproducing a positive drooping characteristic, i. e. decrease ofsynchronous speed with increase of load.

When the atmospheric leak 611! is opera tive, the pressure in chamber 66will equalise with the external atmospheric pressure after a certaindelay, dependent on the adjustment of the restrictor 68-10, with theresult that the effort exertedby the pneumatic buffer, due to theelasticity of its contained air, reverts gradually to zero, so that thedrooping characteristic thereby conferred on the governor is of atemporary nature. Restrictor 68-10 can be adjusted while the governor isrunning.

The spring-rate of the pneumatic buffer, and hence the magnitude of thetemporary drooping characteristic thereby conferred, depends on the rateof volume change of chamber 66 per unit stroke of the bellows disc 62,which can be varied by altering the clearance volume of the chamber.This can be eifected by partially filling the chamber with thin oil,introduced by removing the screw-plug 68. By adjusting the quantity ofoil so introduced the clearance volume can be decreased by apredetermined amount, and the magnitude of the temporary droopcorrespondingly increased from the minimum value obtained when thechamber 66 is empty.

The inherent elasticity of the bellows 63 is additive to the elasticityof the air contained in the chamber 66 and therefore increases themagnitude of the drooping characteristic conferred by the pneumaticbuffer, by an amount which is of a permanent nature since it isunaffected by the action of the leak 61-. The permanent droop soconferred will usually be of small magnitude compared with that of thetemporary droop due to the elasticity of the air contained in chamber66.

The mechanical linkage between the movable member of the motor and thespeeder spring abutment, provided by the lever 43 confers a permanentdrooping characteristic whose magnitude can be varied between positiveand negative limiting values by adjusting the position of fulcrum 45,since the position of the spring abutment thimble 38, as determined bythat of the abutment-locat' g member 4|, and consequently the setting ofthe speeder spring 23, varies linearly with that of piston BI and rod32, the magnitude and algebraic sign of the ratio between thedisplacements of the piston and rod 3|, 32 and of the abutment thimble38 being dependent on the adjustment of the fulcrum 45. This can becarried out while the governor is running.

The basic speeder spring setting can be adjusted by means of the worm 50to vary the axial spacing of the spring abutment thimble 38 from theabutment-locating member 4|, through the action of the lead-screw andnut means 38, 40.

This adjustment, too, can be made while the governor is running. hebasic setting is substantially unafiected by common axial displacementsof the abutment thimble 3B and abutmentlocating member 4| by the lever43, since the helix angle of the worm wheel teeth on the thimble 38 issuch that the full range of axial displacement of the thimble 38relatively to the worm 50 will only rotate the thimble through a smallpart of a complete turn and hence will displace it axially relatively tothe member 4! through a small fraction only of the pitch of thelead-screw 40,

In carrying this invention into practice the construction hereindescribed may be modified in any desirable way Within the competence ofskilled in the art, without departing from. the spirit of the invention,which shall be deemed those to include all such modifications as arewithin the scope of the annexed claims.

I claim:

1. A speed governor for an engine having a power-output-regulator, saidgovernor comprising a body, hydraulic motor means including a movablemember operative on said regulator, a pilot valve adapted to controlsaid motor means. a speeder spring operative on an engine-drivenfiyweight carrier, centrifugal flyweight means mounted on said carrierand exerting on said pilot valve an effort opposed to that of thespeeder spring, a pneumatic bufler comprising a part anchored on thebody and a movable part, a mechanical linkage interconnecting saidmovable part with the pilot valve and with the movable member of themotor in such a way that displacement of said movable member in thesense to reduce the engines power output causes a proportionatedisplacement of the movable part of the buffer causing a proportionatechange of air pressure within the buifer, said change of pressure actingthrough the linkage on the pilot valve in a sense to augment the eifortof the speeder spring, displacement of the movable member of the motorin the opposite sense having a similar but contrary effect, a passageproviding an atmospheric leak from the pneumatic buffer and a manuallyadjustable restrictor for variably restricting said passage.

4. A governor as defined in claim 1 including further a movable speederspring abutment, a mechanical linkage interconnecting the latter saidpilot valve,

accessowith the movable member (of the motor in such a way thatdisplacement :of "said movable mem ber causes a proportionatedisplacement of 'said abutment for varying the effort of the Speederspring, and manually operable means for adjusting said linkage so as tovary'the magnitude and algebraic ign of the ratio of said displacements.

5. A governor as defined in claim 4., .in which the mechanical linkageinterconnecting the movable member of the motor with the'speeder springabutment includes a lever connected to said movable member, :a fulcrumfor said lever mounted on the body, an abutment-locating memberpivotally connected to said lever and movable thereby in a direction:for varying the "speeder-springis effort, and manually operable meansfor 'adj'ust ing the position of the Speeder-spring abutment relativelyto said locating member for varying the speeder-springs effortindependently of such variation thereof as is caused by displacement ofthe movable member of the-motor through the agency of said lever.

6. A governor as defined in claim 5, wherein the means for adjusting theposition of the Speeder-spring abutment relatively to theabutment-locating member includes leadscrew and nut means operativelyconnected to said Speederspring abutment and manually operable Worm andworm-wheel gear means operatively 'connected to said Speeder-springabutment for operating the lead-screw -and mitmeans.

7. A governor as defined in claim 6, wherein the lead-screw is fixed tothe abutment-locating member and the nut is constituted by theSpeederspring abutment itself, the latter being rotatable Withrespect tothe body, and the Worm-wheel being unitary therewith, and the worm beingjournalled in the body.

8. A governor as defined in claim 1, including further a movableSpeeder-spring abutment, a lever interconnecting the latter with thernovalble member of the motor, a fulcrum for said lever adjustablydisplaceable in the direction of the length of the lever with respect tothe body,

8' 7 whereby displacement :of said movable member causes a proportionatedisplacement of the gpeeder-sprin'g abut-ment'ror varying the effort ofthe Speeder-spring, the magnitude and algebraic sign of the ratio "of-said displacements being variable by displacement of said fulcrum, andmanually operable means for adjustably displacing said fulcrum.

9. Aggo verndr as defined in claim 8, whereof the manually operablemeans for displacing the said fulcrum comprise a lead-screw.

l0. A governor ias defined in claim 1, wherein the mechanical linkageinterconnecting the movable member of the motor with the pilot valve.

and with the movable ,part of the pneumatic buffer comprises a leverpivotally connected with the pilot valve and having one end engaged withsaid movable member and the other end connected with said movable part.

11. A governor as defined in claim 1, whereof the pneumatic butlercomprises a chamber of variable volume vented to atmosphere through saidleak-passage, said chamber being provided with a filling hole and aremovable plug for closing said hole, whereby the effective volume ofthe chamber may be decreased to a predetermined extent by introducinginto said chamber, through said hole, a predetermined "quantity of oil.

12. In a governor as defined in claim 1., whereof the pneumatic buffercomprises a chamber vented to atmosphere through said leak-passage, thevolume of said chamber being variable by displacement of the movablepart of the buffer, the method of varying the rate at which thepneumatic effort exerted by the miller changes as said movable part isdisplaced, which method consists in altering the clearance volume of thechamber by partially filling the chamber with oil, the chamber beingprovided (for this pur-' pose with a filling hole and aplug for closingsaid hole after introduction of the oil.

No references cited.

